E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Wednesday.
Woden-es or Odin-es Day, called by the French Mercredi (Mercurys Day). The Persians regard it as a red-letter day, because the moon was created on the fourth day. (Genesis iv. 1419.)
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But the last Wednesday of November is called Black Wednesday.